Research News, Feb 1st, 2012

 Synthesis of Benzothieno (2,3-b)thiophenes, (2,3-b:3,2-d)-dithienothiophenes and Their Selenium Derivatives via Electrophilic Cyclization and McMurry Cyclization

 Weizhi Geng, Hanliu Wang, Zitao Wang, Shaoguang Zhang,

Wen-Xiong Zhang, and Zhenfeng Xi*

Tetrahedron 2012, Accepted.

Benzothieno (2,3-b)thiophenes, (2,3-b:3,2-d)-dithienothiophenes and their selenium derivatives were synthesized in good yields from readily available 3-ethynyllithio-benzo[b]thiophenyllithio compounds, sulfur or selenium, and two equivalents of acid chlorides. Two heteroarene rings were constructed by a twofold cyclization via an acid chloride-induced electrophilic ring-closing and the McMurry cyclization using Zn/TiCl4 reagents.